


Egg-celent expreiments

by Sephypsycologist



Series: Tumblr Requests: Undertale [43]
Category: Undertale (Video Game)
Genre: Environmentalism, Kinda?, Other, Oviposition, Science
Language: English
Status: Completed
Published: 2020-01-16
Updated: 2020-01-16
Packaged: 2021-02-27 07:41:09
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,184
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22273483
Author URL: https://archiveofourown.org/users/Sephypsycologist/pseuds/Sephypsycologist
Summary: Serif's new friend has some science to do and Serif is helping;)((done on request from Serif's lovely creator -w-))
Series: Tumblr Requests: Undertale [43]
Series URL: https://archiveofourown.org/series/800364
Comments: 1
Kudos: 38





	Egg-celent expreiments

Well, maybe volunteering to help with a science experiment wasn’t the smartest thing he’d ever done, but Serif was at least a little excited.

The new little Gaster Sans he’d met was more nerdy than suave, and the two of them had gotten to be very good friends. So when he’d asked if Serif would mind helping him with an experiment, Serif had accepted.

But this was…a little more intimate than he’d expected.

“Um so…? I lay down here?” Serif motioned to the padded table in the center of the room.

“Y-yeah, I know it’s…strange and…” his new friend fidgeted, blushing yellow. Oh, maybe that’s why his name was Goldenrod. “B-but if we can incubate these eggs, then we can save the species! It’s perfectly safe, I swear.”

And when he saw how Goldie’s arms folded over a much bigger tummy than he’d had before, Serif realized he’d tested it on himself first. “Okay then.” No need to fret if Goldie was still here, after all.

Using the provided step stool, Serif settled onto the table in his little hospital gown, the breeze around his booty a little cold.

Goldenrod smiled, still shy, “Thank you, Serif. This is so important for the ecosystem in this world, and I’ll find some way to repay you.”

Scurrying to the machine in the corner of the room, Goldenrod began flipping levers and turning dials, babbling the whole time, “The tubing is coated in anesthetic, so it won’t hurt a bit, and while you’ll feel kinda full, the eggs don’t hurt either once they’re in. It’s kinda strange when they move, but that means it’s working! And that won’t happen for a little while, so no worries!”

Serif blushed as the tube Goldie was talking about slid down on a mechanical arm and started pressing against his booty hole. Oooh, that tingling anesthetic was weiiiird, but as he relaxed into it and it moved in a little more, it felt…sort of good.

He could see the tank with the eggs in it, suspended in a gel sort of stuff, and watched in curiosity as the eggs and gel traveled through the tube. Goldie was talking still.

“The gel is there to keep them inside you for the appropriate time, kind of stops your system from forcing it back out, right? It degrades into pure magic, so you don’t have to worry about needing to eat while they’re, uh, taking up all the space,” Goldie was blushing very hard and purposefully not looking at him, and Serif felt the need to cover his face.

The first egg pushed into him from the tube and Serif squeaked. Oooh, boy, those were a lot heavier than he’d though and…wait a minute. As more eggs and gel slid inside his body, Serif groaned a bit. After the first one, each new egg and the warm gel around it made him fill out more and more, the dark orbs in their pink solution coloring his belly slowly as they took up more of it.

“Is it,” Serif bit back another moan, “Is it supposed to feel good?”

“Um, side effect of the gel but…yeah.” Goldie was smiling a little even if he looked ashamed. “Feel free to do whatever you like while it’s going on. Um…I’ll just, ah, give you some privacy.”

“Nooo,” Serif didn’t want to be alone and feeling the warmth rising in his pelvis, a small tent starting to rise in his gown. “Goldie, just hold my hand? Please?”

Flustered, the scientist shuffled over and sat on the step stool, looking at the floor with a bright yellow skull as he held Serif’s hand.

“Thank you…oh gosh,” Serif purred softly as his face warmed, fully erect now and beginning to pant as more of his stomach was taken up with eggs. So many, and even though it didn’t hurt, he could feel each of the round shapes slip up into him, each stretch of his magic as it pushed out to accommodate.

Serif couldn’t really talk past this, just moaning and huffing as he tried to reach himself to relieve the pressure but…his tummy was too big right now, he just couldn’t.  
“Um,” Goldie sounded so far away even though he was right there, “Let me do something.”

There was a golden glow, and Serif felt something wrap around his shaft. “eh?” he asked, weakly, confused.

“I brought one of my…private inventions. It helps with this,” confessed Goldie as several tendrils held Serif’s legs apart while more slid up and down his shaft and stroked his package.

Whatever it was, Serif was loving it, whimpering and arching, as tingles of pleasure wrapped his whole pelvis. It wasn’t long till he was cumming, bits of purple ooze now decorating the tubing he could see, but the eggs didn’t stop, still filling every inch of space they could take.

Squeezing Goldie’s hand, Serif rode through orgasm after orgasm until he was in a fog of pleasure, and dimly aware when the tube slid out and away.

“Serif?” Goldie’s hesitant voice drifted into his mind, “Are you okay? I didn’t realize you’d like it so much. I’m sorry.”

He found his tongue at last after a bit of searching, “is okay, geeeee.” Yeah, that sounded weird. It made him giggle as he tried to sit up.

That was harder than it should have been, but his tum was soooo full and warm and heavy and it felt nice.

“Are you sure? I wasn’t meaning for the experiment to be so intimate, really…” Goldie looked sad, no, worried. Yeah, worried was the right word.

“No worries. ‘m fine, an’ so are you.” It would take a while for Serif to fully come back to himself after this interesting experience, but he was, indeed, fine, and did not feel badly toward Goldie at all.

\--

Goldie was sure to be there with Serif when it came time to ‘birth’ the eggs. It was surprisingly easy, as the shells were flexible and the little beings inside were octopus-like critters.

“Serif, I’m so so pleased with the results. This proves that monsters can safely incubate gloctopus eggs, which means we can rebuild the population much easier!” Goldie had transferred the newly hatched blue creatures into an aquarium, and Serif grinned as they glowed a soft purple, just like his magic.

“They’re so tiny and cute!” Serif cooed, watching them swim around.

“They are, really, but they get much bigger as adults,” Goldie was equally proud and fascinated, “Really, we’ve done an amazing service to the environment! Though, mostly you. I don’t have a very good capacity.”

“Well,” Serif blushed a bit but tried to act casual, “I wouldn’t say no to doing it again but…can I have more eggs this time?”

Goldie’s glasses slid down on one side with how fast he whipped his head around, but the slow spread of golden blush betrayed his thoughts, “Um…s-sure. Why not?”

Happy and eager, Serif rushed to go change into a gown again. This was going to be fun.


End file.
